Simon, I'm not familiar with the "Newsletter" feature on Civi. What exactly are you looking for here?

If you want to send emails direct from your CRM, the bulk email Mandrill setup described in Tauno's blog post (linked in 3rd comment) is still valid, although lots of those modules have been updates since that article was written so the screenshots might be a little off.

If you want redhen contacts subscribed to a Mailchimp account via a checkbox, the new version of the Mailchimp module (7.x-3.1) allows this using a "Mailchimp Subscription" field that can be added to your RedHen contacts.

Those answers are both specific to the mailchimp/mandrill suite we end up using a lot in our work. For other functionality, if you can be more specific I can tell you if it's something on the RedHen roadmap, in the feature set, or something that you should look to add from the rest of the Drupal contrib space. RedHen is built on top of Drupal in such a way that it can leverage tons of other contrib modules.

I think that for many people, a simple, integrated solution would be interesting. I have seen, but not yet tried out the solution with Mandrill.

What I'm basically looking for is: On the front end: the visitor of the website should be able to sign up to a newsletter (and with this automatically be added to the CRM). A next step would be the possibility to offer several different newsletter to which people can apply.

On the backend:
- Add/remove people from the mailinglist, without deleting them from the CRM (there might be contacts that shouldn't receive an e-mail).
- Sending out newsletters that include content published in Drupal.
- sending out e-mails in batches over a certain period of time.
- Some stats on click-through rate etc.
- Tokens
- probably some other.